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To evaluate the rationality of the cooling system design for a four cylinder engine, computational fluid dynamics method was used to analyze the engine cooling system from layout design, system flowrate determination, flow field of the cooling system and engine temperature field. The optimization design of adding a throttling notch to the cylinder block water jacket was proposed to solve the problem of significant differences in coolant flow velocity in the cylinder block water jacket. The results show that the coolant flow velocity uniformity in cylinder block water jacket is significantly improved, and the wall temperature of each cylinder liner can be reduced by 1~3 °C. The thermal balance test results at an engine speed of 12 000 r/min show that the maximum difference in cylinder temperature is about 4 °C. The oil temperature is about 129 °C, which is controllable (less than 140 °C), indicating that the cooling system of the four cylinder engine is designed reasonably to ensure uniform cooling of each cylinder and oil cooling. [ABSTRACT FROM AUTHOR]

Hydrogen sulfide (H2S) is one of the important gaseous signalling molecules, which plays key roles in various critical biological processes. In this work, we report a novel two-photon near-infrared (TP-NIR) fluorescent probe (MNIR-H2S) for the sensing of mitochondrial H2S in living cells, tissues, zebrafish and nude mice. Using a xanthene dye as a TP-excitation (810 nm) NIR-emission (668 nm) fluorophore, a well-known H2S response moiety with a robust intramolecular charger transfer (ICT) effect can quickly respond to H2S and effectively quench the fluorescence intensity, and an oxonium cation structure serves as a mitochondria-targeting site. Notably, MNIR-H2S displays high sensitivity, high selectivity, low cytotoxicity, powerful mitochondrial localization ability, deep tissue penetration, and a very minimal imaging background. Biological imaging results show the biological application of MNIR-H2S as a robust new tool for use in H2S imaging in biological systems. [ABSTRACT FROM AUTHOR]

In order to obtain the optimized technological parameters of hot air-vacuum combined drying of lettuce, the effects of hot air temperature, intermediate conversion moisture content, slice thickness and vacuum degree (four influence factors) on lettuce drying were explored. The drying time and rehydration ratio of lettuce were the experimental indices, and the relationships between the experimental indices and the influence factors were analyzed by using the response surface methodology. The regression mathematical models were established. The optimized technological parameters of hot air and vacuum combined drying are 50C hot air temperature, 40% intermediate conversion moisture content (w.b.), 20 kPa vacuum degree and 5 mm slice thickness. Practical Applications Combined drying is widely used in food, which is considered as an effective method to achieve energy conservation and shelf life. The objective of this paper was using response surface methodology to obtain optimized hot air vacuum drying parameters for lettuce. The significance of this research can improve the drying efficiency, provide a reference for other fruits and vegetables' drying process optimization and provide a technical basis for the drying of lettuce and the designing of related equipment. [ABSTRACT FROM AUTHOR]